1. Field of the Invention
This invention relates to X-ray spectral analysis and can be used for control of radiation spectra of X-ray generators as well as for analysis of chemical elements composition and atomic structure of specimens by measuring their absorption spectra.
The invention application is the most promising for study of fast processes kinetics when operating with modern high-power pulsed sources, for example with X-ray lasers, synchrotrons, and laser-electron sources on the basis of inverse Compton scattering.
2. The Prior Art
An X-ray spectrometer comprising a crystal dispersing element, translation means of a dispersing element relative to an X-ray beam and means for radiation detection is well-known (E. P. Bertin. Introduction to X-Ray Spectrometric Analysis. New York, Plenum Press, 1978.). The main disadvantage of that spectrometer is a low speed of spectrum measurements, as selection of spectral bands is provided in series by turning the dispersing element and the radiation detector relative to the analyzed X-ray beam. That spectrometer also precludes studying of fast processes in cases wherein conditions of the repeated measurements and exposure to radiation cannot be reproduced with high accuracy.
Also an X-ray spectrometer is known comprising a dispersing element in a form of a curved crystal, means of translation of a dispersing element relative to an X-ray beam and means of radiation detection (A. A. Rusakov. Radiography of metals. M., Atomizdat, 1977). A disadvantage of this spectrometer is connected with the fact that the spectrum measurement using this spectrometer can be provided only in case of sufficiently wide divergence of a primary beam. At the same time modern X-ray radiation generators have a narrow angle divergence, which is why measurements of direct radiation and broad-band absorption spectra using the specified spectrometer are not possible.
An X-ray spectrometer comprising a prism dispersing element, means of translation of a dispersing element relative to an X-ray beam and means of radiation detection (Patent of RF No 2217732, G01N 23/04, 2002) is the closest to the claimed invention from the technical point of view. If a linear arrangement of serially located detectors is used as means of radiation detecting, this spectrometer provides feasibility of a full spectrum registration with a fixed position of a dispersing element. This allows to study the spectra in case of pulsed processes including a single X-ray shot if its power is sufficient for recording a signal with the specified noise-to-signal ratio (Patent of RF No 2217732, G01N 23/04, 2002).
The main disadvantage of this spectrometer is insufficient accuracy of absolute measurements of X-ray photon energies of the recorded spectrum. This disadvantage is caused by the fact that the angular spectrum of radiation dispersed by a prism depends strongly on the angular position of a prism relative to an axis of a primary X-ray beam. This angular position of a prism, however, can be uncontrollably changed as a result of a backlash of translation means of a dispersing element during adjustment procedure. The angular position of the said element may also drift due to heating by intense beam radiation. As a result a real angular position of the prism can substantially differ from a specified value. Furthermore, a primary radiation beam can have a significant cross-section width. This makes it difficult to determine the position of a prism refracting surface relative to the axis of a primary beam. It leads as well to inaccuracy in the angular coordinates determinations. All above mentioned factors cause significant errors of spectrum measurements and complicate the spectrometer adjustment.